1// SPDX-License-Identifier: GPL-2.0
2
3/*
4 * Memory Mapped IO Fixed clock driver
5 *
6 * Copyright (C) 2018 Cadence Design Systems, Inc.
7 *
8 * Authors:
9 * Jan Kotas <jank@cadence.com>
10 */
11
12#include <linux/clk-provider.h>
13#include <linux/of_address.h>
14#include <linux/module.h>
15#include <linux/platform_device.h>
16
17static struct clk_hw *fixed_mmio_clk_setup(struct device_node *node)
18{
19 struct clk_hw *clk;
20 const char *clk_name = node->name;
21 void __iomem *base;
22 u32 freq;
23 int ret;
24
25 base = of_iomap(node, 0);
26 if (!base) {
27 pr_err("%pOFn: failed to map address\n", node);
28 return ERR_PTR(-EIO);
29 }
30
31 freq = readl(base);
32 iounmap(base);
33 of_property_read_string(node, "clock-output-names", &clk_name);
34
35 clk = clk_hw_register_fixed_rate(NULL, clk_name, NULL, 0, freq);
36 if (IS_ERR(clk)) {
37 pr_err("%pOFn: failed to register fixed rate clock\n", node);
38 return clk;
39 }
40
41 ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, clk);
42 if (ret) {
43 pr_err("%pOFn: failed to add clock provider\n", node);
44 clk_hw_unregister(clk);
45 clk = ERR_PTR(ret);
46 }
47
48 return clk;
49}
50
51static void __init of_fixed_mmio_clk_setup(struct device_node *node)
52{
53 fixed_mmio_clk_setup(node);
54}
55CLK_OF_DECLARE(fixed_mmio_clk, "fixed-mmio-clock", of_fixed_mmio_clk_setup);
56
57/**
58 * This is not executed when of_fixed_mmio_clk_setup succeeded.
59 */
60static int of_fixed_mmio_clk_probe(struct platform_device *pdev)
61{
62 struct clk_hw *clk;
63
64 clk = fixed_mmio_clk_setup(pdev->dev.of_node);
65 if (IS_ERR(clk))
66 return PTR_ERR(clk);
67
68 platform_set_drvdata(pdev, clk);
69
70 return 0;
71}
72
73static int of_fixed_mmio_clk_remove(struct platform_device *pdev)
74{
75 struct clk_hw *clk = platform_get_drvdata(pdev);
76
77 of_clk_del_provider(pdev->dev.of_node);
78 clk_hw_unregister_fixed_rate(clk);
79
80 return 0;
81}
82
83static const struct of_device_id of_fixed_mmio_clk_ids[] = {
84 { .compatible = "fixed-mmio-clock" },
85 { }
86};
87MODULE_DEVICE_TABLE(of, of_fixed_mmio_clk_ids);
88
89static struct platform_driver of_fixed_mmio_clk_driver = {
90 .driver = {
91 .name = "of_fixed_mmio_clk",
92 .of_match_table = of_fixed_mmio_clk_ids,
93 },
94 .probe = of_fixed_mmio_clk_probe,
95 .remove = of_fixed_mmio_clk_remove,
96};
97module_platform_driver(of_fixed_mmio_clk_driver);
98
99MODULE_AUTHOR("Jan Kotas <jank@cadence.com>");
100MODULE_DESCRIPTION("Memory Mapped IO Fixed clock driver");
101MODULE_LICENSE("GPL v2");
102